Extensibility Good or Bad

A new topic has been open on the Wiki with a few questions about the 
issue of extensions.

http://esw.w3.org/topic/ExtensibilityGoodOrBad

Feel free to add your opinions, your experiences, and your comments.

-- 
Karl Dubost - http://www.w3.org/People/karl/
W3C Conformance Manager
*** Be Strict To Be Cool ***